Magnesium Battery Electrolyte with Imidazolate Anion

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Solution Overview

Problem

Lithium-ion batteries pose safety risks due to lithium's high reactivity and expense, necessitating an alternative for high energy density batteries, particularly in electric mobility applications, where conventional organic electrolytes are ineffective for magnesium batteries.

Innovation Solution

A magnesium secondary battery system utilizing an electrolyte with a magnesium salt containing an imidazolate anion, specifically designed to facilitate reversible magnesium ion intercalation and extraction between electrodes, using solvents like organic carbonates and ethers, and incorporating active materials capable of reversible magnesium ion storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If lithium-ion batteries are used to achieve high energy density, then energy density is improved, but safety risk increases due to lithium's high reactivity and potential for dendrite formation

Engineering Contradiction:
Improveenergy densityVSAvoidsafety risk
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent replaces expensive and safety-risky lithium with magnesium, which is cheaper, less reactive, and does not form dangerous dendrites. The magnesium anode serves as a safer, more stable alternative that maintains high energy density while eliminating safety concerns associated with lithium's reactivity and dendrite formation

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical parameter from lithium to magnesium, utilizing magnesium's divalent nature (Mg2+) to achieve twice the charge transfer per ion compared to lithium. This parameter change enables high energy density while simultaneously improving safety due to magnesium's lower reactivity and inability to form dendrites

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional organic electrolytes are used in magnesium batteries, then ease of manufacture is improved, but reversibility of magnesium deposition and dissolution is lost due to passivation of the magnesium anode

Engineering Contradiction:
Improveease of manufactureVSAvoidreversibility of magnesium deposition and dissolution
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent employs a composite electrolyte system combining linear carbonate (EC) and cyclic carbonate (DMC) solvents with specific magnesium salts. This composite electrolyte composition prevents passivation of the magnesium anode while maintaining ease of manufacture, enabling reversible magnesium deposition and dissolution that conventional organic electrolytes cannot achieve

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the electrolyte composition parameters by using specific ratios of linear to cyclic carbonates (0.3 to 2.0 by volume) and selecting appropriate magnesium salts with specific anions. These parameter changes transform the electrolyte's properties to prevent anode passivation while maintaining manufacturability and enabling reversible magnesium electrochemistry

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system enables safer, cost-effective magnesium batteries with higher energy density and operational stability at higher voltages, overcoming the limitations of lithium-ion batteries by providing a tailored electrolyte for magnesium batteries.

Implementation Method 1

This ion current is ensured by an ion-conducting electrolyte

Methodology Applied
Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

the reversible electrochemical deposition and dissolution of magnesium at the anode

Methodology Applied
Scientific EffectElectrochemical deposition: Electrodeposition

Implementation Method 3

During discharge, electrons are released at the negative electrode through an oxidation process

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 4

a corresponding amount of electrons is absorbed. Thus, a reduction process takes place at the positive electrode

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 5

an electrolyte system consisting of a solvent and a magnesium salt at least partially dissolved therein, through which charge exchange can take place between the at least one positive and the at least one negative electrode

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 6

an active material capable of reversibly storing and removing magnesium ions... the reversible insertion and removal of magnesium ions into the cathode material

Methodology Applied
Scientific EffectIntercalation: Absorption (physical)

Data Source

PatentEP3113275B1Secondary magnesium battery and electrolyte system and electrode for a secondary magnesium battery
Publication Date: 2021.06.09 VARTA MICRO INNOVATION
  • EP3113275B1 patent drawingFigure 1~2
  • EP3113275B1 patent drawingFigure 3~4
  • EP3113275B1 patent drawingFigure 5

AI summary

A secondary magnesium battery is described, comprising at least one positive electrode containing an active material capable of reversibly inserting and removing magnesium ions, at least one negative electrode containing an active material capable of reversibly inserting and removing magnesium ions, and an electrolyte system consisting of a solvent and a magnesium salt, which is at least partially dissolved in the solvent, allowing charge exchange between the at least one positive and at least one negative electrode. The magnesium salt contains an imidazolate anion of formula I.In this formula, R1 is a residue from the group containing alkyl, aryl, alkyl-aryl, aryl-alkyl, alkyl-O, aryl-O, alkyl-O-alkyl, aryl-O-aryl, alkyl-O-aryl, and aryl-O-alkyl, or an oligo- or polyether residue from the group containing alkyl-[O-alkyl]n, alkyl-[O-alkyl]nO, aryl-[O-aryl]n, aryl-[O-aryl]nO, alkyl-[O-aryl]n, alkyl-[O-aryl]nO, aryl-[O-alkyl]n, and aryl-[O-alkyl]nO, with n = 1 to 800, or a substituted derivative of one of these residues, and R2 and R3 are independent electron-accepting substituents with -I and/or -M effects, which exert the negative Stabilizing the charge of the imidazolate anion. Furthermore, an electrolyte system and a negative electrode for a magnesium battery are described.